Silicon battery and method for assembly

ABSTRACT

A method for forming a battery anode can include: forming a slurry including active material comprising silicon particles, wherein the silicon particles can be derived from silica fumes, depositing the slurry on an current collector, drying the deposited slurry to form a deposited film, and compacting the deposited film to form the battery anode.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.63/254,868, filed 12-OCT-2021 and U.S. Provisional ApplicationNo:63/273,043, filed 28-OCT-2021, each of which is incorporated in itsentirety by this reference.

TECHNICAL FIELD

This invention relates generally to the battery field, and morespecifically to a new and useful system and method in the battery field.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a schematic representation of the method.

FIG. 2 is a schematic representation of an example of preparing anelectrode.

FIG. 3 is a schematic representation of an example of a roll to rollprocess.

FIG. 4A is a schematic representation of an example of a pouch cell thatincludes tabs.

FIG. 4B is a schematic representation of an example of a tab-less pouchcell.

FIG. 5 is a schematic representation of a battery cell assembly process.

FIGS. 6A, 6B, and 6C are schematic representations of exemplaryelectrodes with different tab configurations.

FIGS. 7A-7F are schematic representations of exemplary siliconparticles.

FIGS. 8A-8E are scanning electron micrographs of exemplary siliconparticles.

FIGS. 9A-9C are scanning electron micrographs of exemplary silicon anodefilms with no calendering, 50% calendering (e.g., densification,compaction, etc.), and 30% calendering (e.g., densification, compaction,etc.) respectively.

FIGS. 10A-10C are scanning electron micrographs of exemplary siliconanode films with non-milled silicon particles, milled (e.g., coldwelded) silicon particles without milling the graphite particles, andmilled (e.g., cold welded) silicon particles milled graphite particlesrespectively.

FIG. 11 is a scanning electron micrograph of an exemplary silicon anodefilm that includes silicon particles and C65 carbon black (e.g., thesilicon anode does not include graphite).

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following description of the preferred embodiments of the inventionis not intended to limit the invention to these preferred embodiments,but rather to enable any person skilled in the art to make and use thisinvention.

1. Overview

As shown for example in FIG. 1 , a method for manufacturing a batterycan include: receiving an electrode material S100; forming an electrodeS200; assembling a battery cell S300; optionally, conditioning thebattery cell S400; optionally, assessing a quality of the battery S500(e.g., battery cell, battery pack, etc.); and/or any suitable steps. Thebattery cell preferably includes an anode, a cathode, a separator, ahousing, and an electrolyte; but can additionally or alternativelyinclude any suitable components.

2. Benefits

Variations of the technology can confer several benefits and/oradvantages.

First, variants of the technology can enable drop-in functionality forpreparing battery including silicon in the anode. For example, a siliconanode material can be used in place of, combined with, and/or inaddition to a carbon anode material in the battery manufacture, byincluding the silicon in a common slurry with the graphite (e.g.,without additional processing steps).

However, variants of the technology can confer any other suitablebenefits and/or advantages.

As used herein, “substantially” or other words of approximation (e.g.,“about,” “approximately,” etc.) can be within a predetermined errorthreshold or tolerance of a metric, component, or other reference (e.g.,within 0.001%, 0.01%, 0.1%, 1%, 5%, 10%, 20%, 30%, etc. of a reference),or be otherwise interpreted.

3. Battery

The battery system 100 preferably functions to generate or produceelectrical power and/or provide or supply the electrical power to one ormore loads (e.g., which can function to consume the electrical powersuch as to convert it into another form of energy). The battery systemis preferably a secondary cell (e.g., a rechargeable battery system suchas one where each electrode can operate as an anode 120 or cathode 110),but can additionally or alternatively form primary cells, bipolar cells,and/or any suitable battery cell. The battery system is preferablyoperated (e.g., cycled) between about 2.5 V and 5 V (and/or a rangecontained therein such as 2.5-4.2 V, 2.7 V-4.2 V, 2.5-4 V, 2.7-3.8 V,2.7-4.3 V, etc.), but can be cycled between any suitable voltages (e.g.,less than 2.5 V or greater than 5 V). In some variants, limiting therange of operation voltages can improve the stability and/or longevity(e.g., number of cycles before significant degradation occurs, number ofcycles before critical battery failure, etc.) of the battery system. Thevoltage range that the battery system can be operated over can depend onthe electrode materials, the electrode capacities, the electrodethicknesses, the load, a programmed (or otherwise specified) voltagerange, and/or any suitable properties.

The components of the system can be solid-state, fluid-state (e.g.,liquid, plasma, gas, etc.), gel-state, a combination of states (e.g., ata critical point, a mixed state, one component in a first state andanother component in a second state, etc.), and/or have any suitablestate of matter. The resultant battery can have a solid state build, Limetal build (e.g., lithium-ion or lithium polymer batteries), metal-airbuild (e.g., silicon-air battery), and/or any other suitableconstruction. The resultant battery can be rigid, flexible, and/or haveany other suitable stiffness (e.g., wherein component thicknesses,numerosity, flexibility, rigidity, state of matter, elasticity, etc. canbe selected to achieve the desired stiffness). The resultant battery canbe a pouch cell, a cylindrical cell, a prismatic cell, and/or have anyother suitable form factor.

The electrodes preferably function to generate ions (e.g., electrons)and to make contact to other parts of a circuit (e.g., a load). Thebattery system preferably includes at least two electrodes (e.g., ananode and a cathode), but can include any number of electrodes. Thenumber of cathodes and anodes can be equal, there can be more anodesthan cathodes, or there can be more cathodes than anodes. For example,the battery can include 1, 2, 3, 4, 5, 6, 10, 20, 50, 100, values orranges therebetween, and/or any other suitable number of anodes and/orcathodes. The anodes and/or cathodes can be single-sided, double sided,and/or otherwise configured. When the battery includes multiple anodesand/or cathodes, the anodes and cathodes are preferably interleaved(e.g., alternate in the electrode stack); alternatively, the cathodesand/or anodes can be grouped or stacked together and/or can otherwise bearranged (e.g., a single cathode can be surrounded by a plurality ofanodes dictated by a cell geometry). Each anode of the plurality ofanodes can be the same (e.g., same materials, same physical propertieswithin specification tolerances, same electrical properties, etc.) ordifferent (e.g., different materials, different physical properties,different electrical properties, etc.). Each cathode of the plurality ofcathodes can be the same (e.g., same materials, same physical propertieswithin specification tolerances, same electrical properties, etc.) ordifferent (e.g., different materials, different physical properties,different electrical properties, etc.).

Each electrode is preferably in contact with a collector (e.g., chargecollector, electron collector, hole collector, etc.), which canfunctions to collect and transport charged particles (e.g., electrons).The collector can be different or the same for each electrode. Thecollector is preferably electrically conductive, but can besemiconducting and/or have any suitable conductivity. The collector canbe a wire, a plate, a foil, a mesh, a foam, an etched material, a coatedmaterial, and/or have any morphology. Example collector materialsinclude: aluminium, copper, nickel, titanium, stainless steel,carbonaceous materials (e.g., carbon nanotubes, graphite, graphene,etc.), brass, polymers (e.g., conductive polymers such as PPy, PANi,polythiophene, etc.), combinations thereof, and/or any suitablematerial. The electrode is typically deposited on the collector.However, additionally or alternatively the collector can be fastened to,adhered to, soldered to, integrated with (e.g., coextensive with asubstrate of), and/or can otherwise be interfaced with the electrode.

Each electrode can be a layered material (e.g., alternating stacks ofmaterials such as an active anode that alternates between carbonaceousmaterial and silicon material), a coextensive material (e.g., activematerial can be a substantially homogeneous mixture of components), thinfilms (e.g., 1 nm to 100 µm thick and/or any values or subrangestherein), thick films (e.g., >100 µm thick), and/or have any suitablemorphology.

Each electrode thickness can be any suitable value or range thereofbetween about 1 µm and 1 cm (such as 1 µm, 2 µm, 5 µm, 10 µm, 20 µm, 50µm, 100 µm, 200 µm, 500 µm, 1 mm, 2 mm, 5 mm, 1 cm), a thickness lessthan 1 µm, and/or a thickness greater than 1 cm. The thickness of eachlayer can be the same and/or different. For example, an anode can have athickness approximately equal to 0.1x, 0.2x, 0.5x, 0.8x, 0.9x, 1x,1.05x, 1.1x, 1.2x, 1.5x, 2x, 2.1x, 2.2x, 2.5x, 3x, 5x, 10x, or valuestherebetween of the cathode thickness. In a variation on this example,these ratios can relate the capacity of the anode to the cathode (e.g.,an anode thickness can be determined to have a thickness that will matchan anode capacity to a ratio of the cathode capacity such as in units ofmAh/cm²). Having a thicker anode (e.g., thicker than necessary to matcha cathode capacity) can be beneficial, for example, because as thecathode transfers material to the anode (e.g., during discharging), theanode may not expand by as much as when the anode and cathode havematching capacities. This benefit can be enabled, for instance, by usingan anode material with a large capacity (such as silicon). However, athicker anode can otherwise be beneficial and/or be enabled.

The N/P ratio (e.g., a capacity ratio such as a linear capacity, anareal capacity, volumetric capacity, total capacity, etc. of the anodeto the cathode) is preferably between about 0.5-2 (e.g., 0.5, 0.6, 0.75,0.9, 1, 1.05, 1.1, 1.15, 1.2, 1.25, 1.3, 1.35, 1.4, 1.45, 1.5, 1.6, 1.7,1.75, 1.8, 1.9, 2, values or ranged therebetween, etc.), but can be lessthan 0.5 or greater than 2. A larger N/P ratio can be beneficial forincreasing the stability of the anode (e.g., because the anode will beless lithiated and undergo less volume expansion compared to a batterywith a smaller N/P ratio). The N/P ratio (e.g., an optimal N/P ratio)can be selected based on the anode material (or properties thereof suchas particle or grain size, external expansion coefficient, etc.),cathode material (or properties thereof), battery stability (e.g., atarget stability), battery cycles (e.g., a target number of cycles,minimum number of cycles, etc.), energy density, voltage range,electrode thickness, temperature, cell variation, number of layers,electrolyte composition, and/or can otherwise be selected or tuned.

Each electrode can have a single active surface, two active surfaces(e.g., a top and a bottom surface), be active around all or any portionof the exposed surface, and/or have any suitable number of activesurfaces, where active surfaces can refer to a surface coupled (e.g.,via electrolyte) to another electrode, to an external load (e.g., via acollector), and/or otherwise be defined.

Each electrode preferably has approximately the same capacity (e.g.,within ±1%, ±2%, ±5%, ±10%, ±20%, etc.). However, electrodes can havedifferent capacities. For example, an anode can have a capacityapproximately equal to 0.1x, 0.2x, 0.5x, 0.8x, 0.9x, 1x, 1.05x, 1.1x,1.2x, 1.5x, 2x, 2.1x, 2.2x, 2.5x, 3x, 5x, 10x, and/or valuestherebetween of the cathode capacity (for example, in units of mAh/cm²).However, the anode can have a capacity less than 0.1x or greater than10x the cathode capacity. Having anodes with capacities greater than thecathode can be beneficial for modifying (e.g., improving) a stability ofthe anode, modifying (e.g., controlling) an expansion of the anode,modifying (e.g., decreasing) an amount of anode plating from thecathode, and/or can otherwise be beneficial. Each electrode capacity canbe controlled or modified based on an electrode thickness, an electrodematerial, an electrode doping, an electrolyte, an electrode doping, anelectrode morphology (e.g., porosity, pore volume, pore distribution,etc.), an electrode substrate, and/or any suitable properties.

The electrode substrate (e.g., collector) is preferably a metal (e.g.,aluminium, copper, silver, gold, nickel, alloys thereof or incorporatingthe aforementioned elements, etc.), but can additionally oralternatively include carbonaceous substrates and/or any suitablesubstrate(s). The substrate thickness is preferably between about 5-20µm. However, the substrate thickness can be greater than 20 µm or lessthan 5 µm. In an illustrative example, an anode substrate can be a 9-16µm thick copper foil. In a second illustrative example, a cathodesubstrate can be a 9-20 µm thick aluminium foil. However, any substratecan be used.

3.1 Cathode

The cathode material preferably includes lithium, but can additionallyor alternatively include any suitable cathode materials. Examples oflithium containing cathode materials include: lithium cobalt oxide(LCO), lithium nickel manganese cobalt oxide (NMC), lithium nickelmanganese oxide (LNMO), lithium iron phosphate (LFP), lithium manganeseoxide (LMO), lithium nickel cobalt aluminium oxide (NCA), and/or anysuitable cathode materials. However, any suitable lithium cathode and/orother cathode material can be used.

3.2 Anode

The anode material can include: active material, binder, conductivematerial, and/or any suitable material(s).

Active material of the anode preferably includes silicon material, butcan additionally or alternatively include carbonaceous material and/orany suitable anode material. The active material is preferably asubstantially homogeneous mixture of components, but can be aheterogeneous mixture of components.

The silicon material 124 preferably includes silicon particles 125(e.g., porous particles, solid particles, nanoparticles, meso particle,microparticles, macroparticles, etc.), but can include films and/or anysuitable structure. In variants, the particles can form clusters (e.g.,aggregates), agglomers (e.g., agglomerates, clusters of clusters, etc.),and/or can have any suitable form.

The particles are preferably made of silicon, but can additionally oralternatively include silica (e.g., silicon oxide such as SiO_(x), SiO₂,etc.), and/or any suitable additives or other materials or elements. Thesilicon content of the silicon material is preferably at least 50%(e.g., 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%,95%, 96%, 97%, 98%, 99%, 99.5%, 99.9%, 99.99%, valuestherebetween, >99.99% such as by weight, by volume, by stoichiometricratio, etc.), but can be less than 50% (e.g., can include regions withless than 50% silicon such as carbon rich regions). The remainder of thesilicon content can include oxygen, nitrogen, hydrogen, carbon,magnesium, aluminium, lithium, sodium, halogens, and/or any suitableelements. For example, the elemental composition of the silicon materialcan include SiOC, SiC, Si_(x)O_(x)C, Si_(x)O_(x)C_(x), Si_(x)C_(x),SiO_(x), Si_(x)O_(x), SiO₂C, SiO₂C_(x), SiOC_(Y), SiC_(Y),Si_(x)O_(x)C_(Y), Si_(x)O_(x)C_(x)Y_(x), Si_(x)C_(x)Y_(x), SiO_(x)Y_(x),Si_(x)O_(x)Y_(x), SiO₂CY, SiO₂C_(x)Y_(x), and/or have any suitablecomposition (e.g., include additional element(s)), where Y can refer toany suitable element of the periodic table (e.g., halgoens, chalcogens,pnictogens, group 13 elements, transition metals, alkaline earth metals,alkali metals, etc.) and x is preferably between 0.001 and 0.05 (but canbe less than 0.001 or greater than 0.05). The material composition ofthe silicon material can be isotropic (e.g., homogeneous distribution ofsilicon and other additives, dopants, impurities, etc.) and/oranisotropic (e.g., inhomogeneously distributed silicon and othermaterials such as forming a core-shell like structure). In anillustrative example of an anisotropic material distribution, a surfaceof the silicon material (e.g., a surface exposed to atmosphere or anenvironment proximal the silicon material) can have a higher oxygen orsilica concentration than an interior of the silicon material (e.g., avolume that is not proximal or exposed to the atmosphere orenvironment). However, an engineered material gradient and/or anysuitable material distribution can exist within the silicon material.

In some variants, the silicon material can include carbon. For example,the silicon material can be coated with carbon; form a composite, alloy,compound (e.g., silicon carbide), material, and/or other chemicalspecies with carbon; and/or can otherwise include carbon. The carbon canbe homogeneous distributed or inhomogeneously distributed (e.g., formingone or more carbon rich and/or carbon poor grains, forming carbonclusters, etc.). In these variants, the total carbon content (e.g., byweight, by volume, by stoichiometric ratio, etc.) can be between 1-99%(e.g., where the remainder can include silicon and/or any suitable traceelements) by weight, by volume, by stoichiometry, and/or according toany suitable reference. However, the carbon content can be less than 1%or greater than 99%. In a first specific example, a silicon material caninclude at least 50% silicon, and between 1-45% carbon, where thepercentages can refer to a mass percentage of each component. In thisspecific example, the silicon material can include at most about 5%oxygen. In a second specific example, a silicon material can includeapproximately 85-93% silicon, approximately 2-10% carbon, andapproximately 5-10% oxygen, where the percentages can refer to a masspercentage of each component. However, the silicon particles can includeany suitable carbon composition.

The shape of the particles can be spheroidal (e.g., spherical,ellipsoidal, as shown for example in FIG. 7A, FIG. 7C, FIG. 7F, FIG. 8E,etc.); rod; platelet; star; pillar; bar; chain; flower; reef; whisker;fiber; box; polyhedral (e.g., cube, rectangular prism, triangular prism,frustopyramidal, as shown for example in FIG. 7E or FIG. 8C, etc.);frustoconical, have a worm-like morphology (e.g., vermiform; as shownfor example in FIG. 7B, FIG. 8A, or FIG. 8B; etc.); have a foam likemorphology; have an egg-shell morphology; have a shard-like morphology(e.g., as shown for example in FIG. 7D or FIG. 8D); include one or morestraight edges (e.g., meeting at rounded corners, at sharp corners, etc.as shown for example in FIG. 1E, FIG. 5A, FIG. 5B, FIG. 5C, FIG. 9A,etc.) and/or have any suitable morphology.

The particles can be freestanding, clustered, aggregated, agglomerated,interconnected, and/or have any suitable relation or connection(s). Asan illustrative example (as shown for instance in FIG. 8C or FIG. 10B),a silicon material can include a plurality of fused particles (e.g.,clusters, agglomers, agglomerates, etc.), where each fused particleincludes a plurality of individual particles that have fused (e.g., beencold welded) together (e.g., without substantially changing a morphologyof the underlying particles, by melding the underlying particles atpoints of intersection, by fusing or sealing a surface of the fusedparticle and retaining a surface area of the unfused particles, etc.;with a change in the morphology of the individual particles; etc.).

A characteristic size of the particles is preferably between about 1 nmto about 10000 nm such as 2 nm, 5 nm, 10 nm, 20 nm, 25 nm, 30 nm, 50 nm,75 nm, 100 nm, 125 nm, 150 nm, 175 nm, 200 nm, 250 nm, 300 nm, 400 nm,500 nm, 1000 nm, 1500 nm, 2000 nm, 2500 nm, 3000 nm, 4000 nm, 5000 nm,6000 nm, 7500 nm, 8000 nm, 9000 nm, 9500 nm, 10000 nm, values or rangestherebetween, etc.). However, the characteristic size can additionallyor alternatively be less than about 1 nm and/or greater than about 10000nm. For example, a fused particle and/or cluster (e.g., aggregate) ofsilicon particles can have a characteristic size between about 1 µm and10 µm (e.g., 1-3 µm, 3-5 µm, 5-10 µm, 3-10 µm, 3-7 µm, 1-5 µm, 1-7 µm,0.9-3 µm, 8-12 µm, other values or ranges therein, etc.), and theparticles that make up the fused particle and/or cluster can have acharacteristic size between about 2 and 500 nm (e.g., 1-10 nm, 10-50 nm,10-100 nm, 20-200 nm, 50-500 nm, 50-525 nm, 10-550 nm, 100-500 nm,values or ranges therein, etc.). In variations of this example, thefused particle and/or clusters can form tertiary structures (e.g.,agglomerates, agglomers, etc.) which can have a characteristic sizebetween about 5-100 µm.

The characteristic size can include the radius, diameter, circumference,longest dimension, shortest dimension, length, width, height, pore size,a shell thickness, and/or any size or dimension of the particle. Thecharacteristic size of the particles is preferably distributed on a sizedistribution (e.g., where the characteristic size can uniquely definethe distribution; can be a moment of the distribution; can be associatedwith specific percentiles of the distribution such as the D10, D20, D50,D60, D80, D90, etc. size; etc.). The size distribution can be asubstantially uniform distribution (e.g., a box distribution, amollified uniform distribution, etc. such that the number of particlesor the number density of particles with a given characteristic size isapproximately constant), a Weibull distribution, a normal distribution,a log-normal distribution, a Lorentzian distribution, a Voigtdistribution, a log-hyperbolic distribution, a triangular distribution,a log-Laplace distribution, and/or any suitable distribution. Thecharacteristic size distribution of the particles (particularly, but notexclusively for fused particles) is preferably narrow (e.g., standarddeviation is less than about 20% of a mean of the size distribution),but can be broad (e.g., a standard deviation greater than about 20% of amean of the size distribution), and/or can otherwise be characterized. Anarrow characteristic size distribution can provide a technicaladvantage of enhancing a lifetime and/or stability of the siliconmaterial as some undesirable processes depend on a size of the siliconmaterial (and having more uniform size such as with a narrowdistribution can lead to more uniform degradation within the sample).

The characteristic size (and its associated distributions) are typicallydetermined directly (e.g., by directly imaging the silicon material suchas using scanning electron microscopy, transmission electron microscopy,scanning transmission microscopy, etc.), but can be determinedindirectly (e.g., based on scattering experiments such as dynamic lightscattering; based on optical properties such as bandgap energy, bandgapwidth, etc.; based on x-ray scattering such as based on a width of x-rayscattering; etc.), and/or can otherwise be determined.

The particles can be solid, hollow, porous, as shown for example inFIGS. 7A-7F or FIGS. 8A-8E, and/or have any structure.

The silicon material can be crystalline, amorphous, nanocrystalline,protocrystalline, and/or have any suitable crystallinity. When thesilicon material (e.g., particles thereof) include crystalline regions,the silicon material is preferably polycrystalline, which can provide atechnical advantage of accommodating mechanical or other stresses thatthe silicon material undergo. However, the silicon material can bemonocrystalline. In some examples, the silicon particles can includecrystalline regions and non-crystalline regions (e.g., amorphousregions).

The exterior surface of the silicon material is preferably substantiallysealed (e.g., hinders or prevents an external environment frompenetrating the exterior surface). However, the exterior surface can bepartially sealed (e.g., allows an external environment to penetrate thesurface at a predetermined rate, allows one or more species from theexternal environment to penetrate the surface, etc.) and/or be open(e.g., porous, include through holes, etc.). The exterior surface can bedefined by a thickness or depth of the silicon material. The thicknessis preferably between about 1 nm and 10 µm (such as 1 nm, 2 nm, 3 nm, 5nm, 10 nm, 20 nm, 50 nm, 100 nm, 200 nm, 500 nm, 1 µm, 2 µm, 5 µm, 10µm, values therebetween), but can be less than 1 nm or greater than 10µm. The thickness can be homogeneous (e.g., approximately the samearound the exterior surface) or inhomogeneous (e.g., differ around theexterior surface).

In specific examples, the exterior surface can be welded, fused, melted(and resolidified), and/or have any morphology. For example, the siliconparticles can be cold welded (e.g., as disclosed in U.S. Pat.Application 17/824,627 titled ‘SILICON MATERIAL AND METHOD OFMANUFACTURE’ filed 25-MAY-2022, which is incorporated in its entirety bythis reference).

The (specific) surface area of the exterior surface of the siliconmaterial is preferably small (e.g., less than about 0.01, 0.5 m²/g, 1m²/g, 2 m²/g, 3 m²/g, 5 m²/g, 10 m²/g, 15 m²/g, 20 m²/g, 25 m²/g, 30m²/g, 50 m²/g, values or between a range thereof), but can be large(e.g., greater than 10 m²/g, 15 m²/g, 20 m²/g, 25 m²/g, 30 m²/g, 50m²/g, 75 m²/g, 100 m²/g, 110 m²/g, 125 m²/g, 150 m²/g, 175 m²/g, 200m²/g, 300 m²/g, 400 m²/g, 500 m²/g, 750 m²/g, 1000 m²/g, 1250 m²/g, 1400m²/g, ranges or values therebetween, >1400 m²/g) and/or any suitablevalue.

The (specific) surface area of the interior of the silicon material(e.g., a surface exposed to an internal environment that is separatedfrom with an external environment by the exterior surface, a surfaceexposed to an internal environment that is in fluid communication withan external environment across the exterior surface, interior surface,etc.) is preferably large (e.g., greater than 10 m²/g, 15 m²/g, 20 m²/g,25 m²/g, 30 m²/g, 50 m²/g, 75 m²/g, 100 m²/g, 110 m²/g, 125 m²/g, 150m²/g, 175 m²/g, 200 m²/g, 300 m²/g, 400 m²/g, 500 m²/g, 750 m²/g, 1000m²/g, 1250 m²/g, 1400 m²/g, ranges or values therebetween, >1400 m²/g),but can be small (e.g., less than about 0.01, 0.5 m²/g, 1 m²/g, 2 m²/g,3 m²/g, 5 m²/g, 10 m²/g, 15 m²/g, 20 m²/g, 25 m²/g, 30 m²/g, 50 m²/g,values or between a range thereof). In some variations, the internalsurface area can be less than a threshold surface area (e.g., 200 m²/g,300 m²/g, 500 m²/g, 750 m²/g, 1000 m²/g, 1500 m²/g, 2000 m²/g, 5000m²/g, etc.), which can provide a technical advantage of limitingoxidation of the silicon material prior to the formation of an externalsurface (e.g., with a lower surface area, sealed external surface,etc.). However, there need not be a threshold upper surface area (e.g.,by controlling an environment to have less than a target oxygenconcentration that can depend on the surface). However, the surface areaof the interior can be above or below the values above, and/or be anysuitable value.

In some variants, the surface area can refer to a Brunner-Emmett-Teller(BET) surface area. However, any definition, theory, and/or measurementof surface area can be used. The surface area can be determined, forexample, based on calculation (e.g., based on particle shape,characteristic size, characteristic size distribution, etc. such asdetermined from particle imaging), adsorption (e.g., BET isotherm), gaspermeability, mercury intrusion porosimetry, and/or using any suitabletechnique. In some variations, the surface area (e.g., an internalsurface area) can be determined by etching the exterior surface of thematerial (e.g., chemical etching such as using nitric acid, hydrofluoricacid, potassium hydroxide, ethylenediamine pyrocatechol,tetramethylammonium hydroxide, etc.; plasma etching such as using carbontetrafluoride, sulfur hexafluoride, nitrogen trifluoride, chlorine,dichlorodifluoromethane, etc. plasma; focused ion beam (FIB); etc.), bymeasuring the surface area of the material before fusing or forming anexternal surface, and/or can otherwise be determined. However, thesurface area (and/or porosity) can be determined in any manner.

In some variations, the silicon material (e.g., silicon particles) caninclude a coating. The coating is preferably a carbonaceous coating(e.g., an inorganic carbon coating, polymer coating, etc.). However, anysuitable coating can be used. The coating material can be the same asand/or different from the binder and/or conductive additive materials(e.g., where coating material is accounted for as a portion of theactive materials in the anode). However, any suitable coating materialcan be used. As an illustrative example, silicon particles can be coatedwith polyacrylonitrile (e.g., PAN). A coating thickness is preferably1-10 nm. However, the coating thickness can be less than 1 and/orgreater than 10 nm,

In specific example, a silicon material can include a coating asdisclosed in (e.g., a coated silicon material can be as disclosed in)U.S. Pat. Application Number 17/890,863 titled ‘SILICON MATERIAL ANDMETHOD OF MANUFACTURE’ filed 18-AUG-2022, which is incorporated in itsentirety by this reference.

The silicon material preferably has a small external expansion (e.g.,less than about 30% external expansion, less than 15%, 0% externalexpansion, compression, etc.), where the external expansion can be avolumetric, areal, linear, and/or other expansion (e.g., in response totemperature changes, in response to swelling due to chemicals, inresponse to lithiation, etc.). However, the silicon material can haveany suitable external expansion.

In some variations, the silicon material can be a material as disclosedin U.S. Pat. Application No: 17/525,769 titled ‘SILICON MATERIAL ANDMETHOD OF MANUFACTURE’ and filed 12-NOV-2021, PCT Publication No:WO2022104143 titled ‘METHOD OF MANUFACTURE OF POROUS SILICON’ and filed12-NOV-2021, U.S. Pat. Application No: 17/841,435 titled ‘SILICONMATERIAL AND METHOD OF MANUFACTURE’ and filed 15-JUN-2022, U.S.Application No: 17/824,627 titled ‘SILICON MATERIAL AND METHOD OFMANUFACTURE’ filed 25-MAY-2022, U.S. Application No: 17/890,863 titled‘SILICON MATERIAL AND METHOD OF MANUFACTURE’ filed on 18-AUG-2022, eachof which is incorporated in its entirety by this reference. However, anysuitable material can be used.

Carbonaceous material of the active material preferably contributes tothe capacity of the active material. However, the carbonaceous materialbe a noncontributor to the capacity. The carbonaceous material ispreferably graphitic material (e.g., graphite, graphene, carbonnanotubes, carbon nanoribbons, carbon quantum dots, etc.). However,additionally or alternatively, any suitable carbonaceous material can beincluded.

The graphitic material 126 preferably includes graphite particles 127.However, additionally or alternatively, graphite films, graphite sheets,shards, and/or can have any suitable morphology. The graphite particlesare preferably spheroidal (e.g., with a sphericity greater than about0.95). However, the graphite particles can additionally or alternativelybe ellipsoidal, fiber-shaped, irregular-shape, polyhedral, and/or canhave any suitable shape. A characteristic size (e.g., diameter, radius,circumference, largest aspect, shortest aspect, etc. where thecharacteristic size can refer to a mean size, D10, D90, D25, D75, etc.of a particle size distribution) of the graphite particles is preferablybetween about 10 µm and 50 µm. However, the characteristic size can beless than 10 µm and/or greater than 50 µm. In some variants, thegraphitic particles can be broken into shard like morphologies (e.g., bymilling, comminution, etc.) as shown for example in FIG. 10B or FIG.10C.

In a first specific example, the active material can include about30-50% silicon particles and/or silicon materials (e.g., by mass, byvolume, by stoichiometry, by particle count, etc.) and about 50-70%graphitic material (e.g., by mass, by volume, by stoichiometry, byparticle count, etc.). In a second specific example (as shown forinstance in FIG. 11 ), the active material can be composed essentiallyof (e.g., 99%, 99.9%, 99.95%, 99.99%, etc.) silicon particles. However,the active material can include any suitable amount of silicon particles(and/or silicon materials such as 10-90% by mass, volume, stoichiometry,particle count, etc.), graphitic material (e.g., graphite particles;such as 10-90% by mass, volume, stoichiometry, particle count, etc.),and/or any suitable components.

The binder 129 can functions to secure (e.g., adhere) the electrode tothe substrate and/or a housing (e.g., case) of the battery system,secure (e.g., bond, adhere, laminate, etc. such as to maintainelectrical contact between, a threshold spacing between, etc.) activematerial together (e.g., adhere silicon particles to other siliconparticles, adhere silicon particles to graphitic particles, etc.),and/or can otherwise function. The binder can be electricallyinsulating, electrically conductive, semiconducting, and/or have anysuitable electrical conductivity. Examples of binders include:carboxymethyl cellulose (CMC), styrene-butadiene rubber (SBR),poly(acrylic acid) (PAA), sodium alginate (SA), polyvinylidene fluoride(PVDF), polyaniline (PANI),poly(9,9-dioctylfluorene-cofluorenone-co-methyl benzoic ester) (PFM),polytetrafluoroethylene (PTFE), poly(ethylene oxide) (PEO), polyvinylalcohol (PVA), polyacrylonitrile (PAN), sodium carboxymethyl chitosan(CCTS), poly(3,4-ethylenedioxythiophene) polystyrene sulfonate(PEDOT:PSS), 3,4-propylenedioxythiophene (ProDOT), dopaminehydrochloride, polyrotaxanes, polythiophene, combinations thereof,and/or any suitable binder. In an illustrative example, an approximately1:1 mixture (by mass, by volume, by stoichiometry, etc.) of SBR to CMCcan be used as a binder. In some variations, the binder can be a coatingof the silicon particles and/or graphitic particles.

The conductive material 128 can function to modify an electricalconductivity of the electrode (e.g., to ensure that the electrode has atleast a threshold electrical conductivity, to ensure that the electrodehas at most a threshold electrical conductivity, to ensure that theactive material is electrically connected to the collector throughoutthe electrode, etc.). Examples of conductive materials include: carbonsuper P, acetylene black, carbon black (e.g., C45, C65, etc.),mesocarbon microbeads (MCMB), graphene, carbon nanotubes (CNTs) (e.g.,single walled carbon nanotubes, multiwalled carbon nanotubes,semi-conducting carbon nanotubes, metallic carbon nanotubes, etc.),reduced graphene oxide, graphite, fullerenes, conductive polymers,combinations thereof, and/or any suitable material(s).

In a specific example of an anode composition, the anode can includeabout 70% (by mass, by volume, by stoichiometry, etc.) active material,about 20% (by mass, by volume, by stoichiometry, etc.) conductivematerial, and about 10% (by mass, by volume, by stoichiometry, etc.)binder. In a second specific example of an anode composition, the anodecan include about 60-95% (by mass, by volume, by stoichiometry, etc.)active material, about 0-20% (by mass, by volume, by stoichiometry,etc.) conductive material, and about 0-20% (by mass, by volume, bystoichiometry, etc.) binder (including any suitable range or combinationcontained therein). However, the anode can include any suitablematerial(s) and/or composition.

3.3 Separator

The separator 130 preferably functions to hinder, slow, or prevent ananode and cathode from electrically contacting one another (therebyshorting the battery) while allowing ions (e.g., lithium cations) topass through the separator. The separator is preferably flexible, butcan be rigid and/or have any suitable mechanical property(s). Theseparator(s) are preferably ionically conductive, but can be ionicallyinsulating, promote (or hinder) ion diffusion, and/or have any suitableionic conductivity. The separator(s) can be permeable to electrolyte(e.g., be porous), can release electrolyte, can pump electrolyte, besolid, include through holes, be mesh, have unidirectional pathways,and/or can otherwise facilitate a (real, apparent, or effective)transfer of electrolyte from one side of the separator to the other. Atleast one separator is preferably arranged between each cathode/anodepair. However, the separator(s) can otherwise be arranged. The separatorcan be equidistant between the cathode and anode, closer to (e.g.,proximal) the anode, or closer to (e.g., proximal) the cathode. However,the separator can otherwise be arranged. The separator preferably has athickness between about 10 µm and 50 µm, but can be thinner than 10 µmor thicker than 50 µm.

The separator can be made of or include ceramics, gels, polymers,plastics, glass, wood, and/or any suitable materials. In some variants,a separator referred to as a “dry cell separator” can be used. Examplesof separator materials include: polyolefin, polypropylene, polyethylene,combinations thereof (e.g., a mixture or blend of PP and PE), and/or anysuitable separator material(s). In some variants, the separator can be amulti-layered separator. For instance, apolypropylene/polyethylene/polypropylene separator or a ceramic coatedseparator (e.g., ceramic coated PP, ceramic coated PE, ceramic coatedPP/PE mixture, etc.) can be used. However, any suitable separator can beused.

In some variants, an ionic conductive polymer can be used as theseparator and/or as an ionic conductive pathway (e.g., as electrolyte,as conductive material, etc.). The ionic conductive polymer can be mixedin and/or coat the anode and/or cathode and form an ionic conductivenetwork throughout the cell. However, the ionic conductive polymer canotherwise be arranged.

3.4 Electrolyte

The electrolyte 140 preferably functions to electrically connectanode(s) to cathode(s) and enable or promote the movement of ions (butpreferably not electrons) between the electrodes. However, theelectrolyte can otherwise function. The electrolyte can be solid-phase,fluid phase (e.g., liquid-phase), and/or any suitable phase. Forexample, the electrolyte can be or include: a gel, a powder, a saltdissolved in a solvent, an acid, a base, a polymer, a ceramic, a salt(e.g., a molten salt), a plasma, ionic liquids, and/or have any suitablestate or combination thereof of matter. The electrolyte can includeorganic materials, inorganic materials, and/or combinations thereof.

Examples of electrolytes (e.g., electrolyte salts), particularly but notexclusively for use with lithium ion batteries, include: lithiumlanthanum titanates (e.g., Li_(0.34)La_(0.51)TiO_(2.94),Li_(0.75)La_(0.5)TiO₃, (Li_(0.33)La_(0.56))_(1.005)Ti_(0.99)Al_(0.01)O₃,etc.), lithium aluminium phosphates (e.g.,Li_(1.3)Al_(0.3)Ti_(1.7)(PO₄)₃, Li_(1.5)Al_(0.5)Ge_(1.5)(PO₄)₃, etc.),lithium zirconates (e.g., Li₇La₃Zr₂O₁₂, Li_(6.55)La₃Zr₂Ga_(0.15)O₁₂,Li_(6.4)La₃ Zr₂Al_(0.2)O₁₂, etc.), lithium silicon phosphates (e.g.,Li_(3.25)Si_(0.25)P_(0.75)O₄), lithium germanates (e.g.,Li_(2.8)Zn_(0.6)GeO₄, Li_(3.6)Ge_(0.8)S_(0.2)O₄, etc.), lithiumphosphorous oxynitrides (e.g., Li_(2.9)PO_(3.3)N_(0.46)), lithiumphosphorous sulfides (e.g., Li₇P₃S₁₁, Li₁₀GeP₂S₁₂,Li_(3.25)Ge_(0.25)P_(0.75)S₄, Li_(3.4)Si_(0.4)P_(0.6)S₄, Li₃PS₄, etc.),lithium silicon phosphates (e.g., Li_(3.5)Si_(0.5)P_(0.5)O₄), lithiumargyrodites (e.g., Li₆PS₅Br, LiPS₅Cl, Li₇PS₆, Li₆PS₅I, Li₆PO₅Cl, etc.),lithium nitrides (e.g., Li₃N, Li₇PN₄, LiSi₂N₃, etc.), lithium imide(e.g., Li₂NH), lithium borohydride (e.g., LiBH₄), lithium aluminiumhydride (e.g., LiAlH₄), lithium amides (e.g., LiNH₂, Li₃(NH₂)₂I, etc.),lithium cadmium chloride (e.g., Li₂CdCl₄), lithium magnesium chloride(e.g., Li₂MgCl₄), lithium zinc iodide (e.g., Li₂ZnI₄), lithium cadmiumiodide (e.g., Li₂CdI₄), lithium chlorate (e.g., LiClO₄), lithiumbis(trifluoromethanesulfonyl)imide (e.g., LiC₂F₆NO₄S₂), lithiumhexafluroarsenate (e.g., LiAsF₆), lithium hexaflurophosphate (e.g.,LiPF₆), combinations thereof, and/or any suitable electrolytes (e.g.,electrolyte salts, for instance replacing lithium with the appropriateion associated with a cathode of the battery).

Examples of matrices (e.g., gels, hydrogels, polymers, solvents, etc.)can include: poly(ethylene oxide) (PEO), poly(vinylidene fluoride)(PVDF), polyacrylonitrile (PAN), poly(methyl methacrylate) (PMMA),ethylene carbonate (EC), diethyl carbonate (DEC), dimethyl carbonate(DMC), propylene carbonate (PC), polyethylene glycol (PEG), glycerol,water, combinations thereof, and/or any suitable matrix can be used.Typically, an electrolyte salt is dissolved in the matrix to aconcentration between about 0.1 M and 10 M, but the concentration of theelectrolyte salt can be less than 0.1 M or greater than 10 M.

In some examples, a mixture of inorganic and organic electrolytes can beused such as: Li_(6.4)La₃ Zr₂Al_(0.2)O₁₂ in PEO/LiTFSI,Li_(1.5)Al_(0.5)Ti_(1.5)(PO₄)₃ in PVDF/LiClO₄, orLi_(0.33)La_(0.557)TiO₃ in PAN/LiClO₄. However, any pure or combinationof electrolytes can be used.

In some variants, the electrolyte can include one or more additives,which can function to facilitate (or hinder) the formation of theinterfacial layer. Examples of additives include: vinylene carbonate(VC), fluoroethylene carbonate (FEC), propylene carbonate (and itsderivatives), ammonium perfluorocaprylate (APC), vinyl ethylenecarbonate (VEC), maleimides (e.g., ortho-phenylenedimaleimide,para-phenylenedimaleimide, meta-phenylenedimaleimide, etc.), glycolide,tetraoxaspiro[5,5]undecanes (TOS; such as3,9-Divinyl-2,4,8,10-tetraoxaspiro[5,5]undecane), poly-ether modifiedsiloxanes, combinations thereof, and/or other additives.

In some variants, the separator and electrolyte can be the same and/orintegrated together. For example, the separator and/or the electrolytecan include a lithium ion conductive glass or ceramic material such as:lithium lanthanum titanate (LLTO; e.g., Li_(3x)La_(⅔-x)TiO₃ for o<x<⅔such as x=0.11), lithium lanthanum zirconate (LLZO; e.g., Li₇La₃Zr₂O₁₂),lithium lanthanum zirconium tantalate (LLZTO; e.g.,Li_(6.75)La₃Zr_(1.75)Ta_(0.25)O₁₂), lithium aluminium germaniumphosphate (LAGP; e.g., Li_(1.5)A1_(0.5)Ge_(1.5)P₃O₁₂), lithium aluminiumsilicon phosphorous titanium oxide (LASPT; e.g., Li₂Al₂SiP₂TiO₁₃),combinations thereof, and/or any suitable materials. However, anysuitable lithium-ion conductive glass or ceramic material can be used.

The battery system preferably includes a housing 140 (e.g., container),which functions to enclose the electrodes, electrolyte, separator,and/or collector. The housing can function to prevent shorting of theelectrodes resulting from contact with objects in the externalenvironment. The housing can be made of metal (e.g., steel, stainlesssteel, etc.), ceramics, plastic, wood, glass, and/or any suitablematerials. Examples of housing shapes include round (e.g., coin, button,cylindrical, etc.), not round, flat (e.g., layer built, pouch, etc.),prismatic (e.g., square, rectangular, etc.), and/or any suitable shape.The housing is preferably electrically insulated from the electrodes.However, in some variations, the housing can be in electrical contactwith one or more electrodes (e.g., or more anode in a battery thatincludes more than one anode, one or more cathode in a battery thatincludes more than one cathode, etc.).

The housing preferably includes two terminals (e.g., one positive andone negative), but can include more than two terminals (e.g., two ormore positive terminals, two or more negative terminals), a singleterminal, and/or any number of terminals. The terminals can function toconnect the battery electrodes to a load. Examples of terminals includecoiled terminals, spring terminals, plate terminals, and/or any suitableterminals.

The housing can be sealed using adhesive, fastener(s), connector(s),binder(s), physical seal, chemical seals, electromagnetic seals, and/orany suitable connectors or sealing mechanism.

In a specific example, a battery can include any suitable battery asdisclosed in U.S. Pat. Application No: 17/672,532 titled ‘SILICON ANODEBATTERY’ filed 15-FEB-2022, which is incorporated in its entirety bythis reference.

4. Method

The method can function to manufacture a battery (e.g., a battery asdescribed above). The method can include: producing an electrodematerial S100, producing an electrode S200, assembling the battery S300,conditioning the battery S400, assessing the battery S500, and/or anysuitable steps. The method and/or steps thereof can be performed in asingle chamber (e.g., a furnace, an oven, etc.) and/or in a plurality ofchambers (e.g., a different chamber for each step or substep, a heatingchamber, a coating chamber, a milling chamber, a washing chamber, etc.).The method (and/or steps thereof) can be performed in a roll-to-rollprocess, in a batch process, and/or in a any suitable process.

Producing an electrode material S100 can function to make (e.g.,produce, manufacture, synthesize, etc.) an active material for a cathodeand/or anode. S100 can additionally or alternatively include making anysuitable battery component (e.g., binder, conductive additive,separator, housing, electrolyte, etc.). In a first specific example, acathode active material can be produced by forming oxides of lithiumand/or any suitable metals (e.g., manganese for LMO; nickel, cobalt, andaluminium for NCA; manganese and nickel for LMNO; iron for LFP; etc.)such as by calcinating raw materials (and/or refining the raw materialsto achieve a target metal composition); sintering the oxides; andoptionally comminuting the sintered oxides. In a second specificexample, an anode active (e.g., silicon particles thereof) material canbe produced by reducing a silica precursor by: optionally purifying thesilica precursor, exposing the silica to reaction modifiers (e.g.,reducing agents such as magnesium, aluminium, etc.; thermal modifierssuch as salt; etc.), optionally purifying the silica and reactionmodifier mixture, optionally comminuting the silica (e.g., using a ballmill), reducing the silica to silicon (e.g., by heating the silica andreaction modifier to a reducing temperature), optionally purifying thesilicon, optionally processing the silicon, and/or any suitable steps orprocesses. Examples of silica precursors include: waste silica (e.g.,silica generated as a byproduct from another process such as waste,residual, etc. silica from a silicon purification process; silicaproduced during silicon production for solar, semiconductor, etc.;silica that would otherwise be disposed of; etc.), recycled silica(e.g., silica recycled or repurposed after a different use), pristinesilica (e.g., newly manufactured silica), and/or any suitable silicastarting material. The silica precursor is preferably silica fumes(e.g., fumed silica, fume silica, Cabosil fumed silica, aerosil fumedsilica, etc.). However, the silica precursor can additionally oralternatively include sol-gel silica (e.g., silica prepared according tothe Stöber method), diatoms, glass, quartz, sipernat silica,precipitated silica, silica gels, silica aerogels, decomposed silicagels, silica beads, silica sand, and/or any suitable silica material.

However, an electrode material (e.g., electrode active material) can bemanufactured in any manner.

Producing an electrode S200 functions to manufacture (e.g., prepare,make, synthesize, form, etc.) an electrode. Each electrode (e.g., anode,cathode) can be processed and/or formed in the same or a differentmanner. The electrodes are preferably manufactured by casting a film ofelectrode material on a current collector. The electrode material ispreferably cast from a suspension (e.g., solution, slurry, mixture,colloid, gel, etc.). Each electrode suspension can include: one or moresolvent (e.g., water, organic solvent), binder (e.g., functional to bindelectrode material together, to bind electrode material to thecollector, etc. such as polymers), conductive material (e.g., conductivecarbon additives), active material (e.g., anode active material, cathodeactive material, etc.), and/or any suitable additives or materials withany suitable concentration or relative concentration.

However, the electrode material can be cast from solid state, gas state,plasma state, liquid state, and/or any suitable state or mixture ofmaterials. However, the electrodes can additionally or alternatively begrown, deposited, transferred to, and/or otherwise be formed on thecollected. The electrodes can be produced in a roll-to-roll process,batch process, and/or using any suitable process. As an example, theelectrodes can be produced using a coating machine (e.g., coater).However, any suitable tool(s) can be used to produce the electrodes.

As shown for example in FIG. 2 , S200 can include: receiving (e.g.,forming) a suspension of electrode material S205 (e.g., from amanufacturer, from individual components, from materials as prepared inS100, etc.); optionally, processing the suspension S210 (e.g.,dispersing the suspension, agitating the suspension, mixing thesuspension, etc.); casting the electrode S220(e.g., by depositing theelectrode material on an collector); optionally, drying the electrodeS240; optionally, compacting the electrode S260 (e.g., densifying,calendering, etc.); optionally, sizing the electrode S280 (e.g., cuttingthe electrode); and/or any suitable steps.

Processing the suspension S210 can function to improve a homogeneity ofthe suspension, disperse materials that have settled within thesuspension, and/or can otherwise function. The suspension can beprocessed in a fluidic chamber (e.g., microfluidic channel, microfluidicchannel, etc.), vat (e.g., mixing basin), grinder, and/or in anysuitable mixing vessel. The suspension can be mixed, for instance, usingagitators, turbulators, blowers, fans, blades, paddles, stirrers (e.g.,magnetic stirrers), shakers, speakers, grinders (e.g., ball mill),and/or any suitable components.

Components of the suspension can be added simultaneously and/orsequentially. For example, an anode slurry (e.g., slurry for making ananode) can be formed (e.g., processed) by simultaneously mixing anodeactive material, binder, and/or conductive material in a solvent (e.g.,a mixture of water and ethanol). In a second example, an anode slurrycan be formed by sequentially mixing anode active material in a solvent(e.g., a mixture of water and ethanol with a composition between 0%water and 100% water by mass, by volume, by stoichiometry, etc.),followed by mixing conductive material, followed by mixing binder. In avariation of the second example, the anode active material can besequentially mixed for instance by first mixing silicon material in thesolvent then graphite material (or vice versa). In a second variation(that can be combined with or separate from the first variation), thebinder can be sequentially mixed in the suspension for instance by firstmixing CMC in the suspension before mixing SBR in the suspension (orvice versa). However, the slurry can otherwise be formed ormanufactured.

Casting the electrode functions to dispose electrode material on acollector. The electrode can be cast on a single side (e.g., broad face)of the collector and/or multiple sides (e.g., broad faces such as on twoopposing sides) of the collector. The electrode suspension can be castusing drop-casting (e.g., with a doctor blade to achieve a targetthickness), spin coating, slot-die coating, spray coating, brushcoating, powder coating, printing, air knife coating, anilox coating,flexo coating, gap coating, gravue coating, dip coating, kiss coating,roller coating, extrusion coating (e.g., curtain coating, slide coating,slot die bead coating, etc.), and/or in any manner.

In some variants, a dry electrode casting process can be used whereelectrode material is deposited without dispersing the electrodematerial in a slurry.

The collector is preferably a foil but can have any suitable geometry.The collector is preferably aluminium (e.g., 5-15 µm thick aluminiumfoil) for the cathode and copper (e.g., 5-10 µm thick copper foil) forthe anode, but can be made of any suitable materials. The same ordifferent casting process can be used for each electrode.

Drying the electrode S240 functions to remove excess solvent from thecast electrode. Drying the cast electrode can additionally oralternatively function to partially densify the cast electrode, annealthe cast electrode (e.g., modify or change a phase of electrodematerials), cyclize a polymer (e.g., cyclize PAN), crosslink one or morepolymers, and/or can otherwise function.

The cast electrode (e.g., wet film, cast film, wet electrode film, wetcathode film, wet anode film, etc.) is preferably dried at a temperaturebelow a carbonization temperature of a polymer (e.g., polymericconstituent of the electrode). For instance, the cast electrode can bedried at a temperature between about 0° C. and 200° C. However, in somevariants drying can be performed at a temperature greater than 200° C.(e.g., to partially or fully carbonize polymer) and/or at a temperatureless than 0° C.

In some variations, the cast electrode can be dried under vacuum, usingdry air (e.g., air, gas, etc. with a relative humidity less than about40%), and/or can be dried in any manner.

Densifying the electrode S360 preferably functions to increase a densityof the electrode film (e.g., cast electrode, dried electrode, driedelectrode film, dry electrode, etc.), which can improve the battery’senergy density, charge/discharge rates, wettability, cycle life,stability, durability, and/or other properties of the battery.Densifying the electrode can additionally or alternatively enhance acontact (e.g., electrical contact) between components of the electrodeand/or can otherwise function (as shown for example by comparing the SEMimages in FIG. 9A, FIG. 9B, and FIG. 9C).

Densifying the electrode can include compacting the electrode (e.g.,using a compactor), calendering the electrode (e.g., using a calender),pressing the electrode (e.g., using a pressing mill), and/or otherwisedensifying the electrode. The electrode is typical densified (e.g., adensity of the electrode is increased by) between about 10% and 75%(e.g., 10%, 15%, 20%, 25%, 30%, 33%, 40%, 50%, 55%, 60%, 66%, 70%, 75%,values or ranges therebetween, etc.). For instance, an electrode canhave a density of about 1 g/cm³ before densification and a density ofabout 1.3 to 1.5 g/cm³ after densification. Typically, too muchdensification will result in a silicon material that undergoes greaterthan a threshold and/or target external expansion (e.g., duringlithiation which can result in degradation of a silicon anode resultingfrom delamination, particle degradation, repeated SEI layer formationand cracking, etc.). However, the electrode can be densified by greaterthan 75% (e.g., for applications where higher densities are acceptable)and/or less than 10%.

The electrode(s) can be densified at room temperature (e.g., about 20°C., 25° C., 30° C., etc.), at a temperature less than room temperature(e.g., about 0° C., about 10° C., <0° C., etc.), and/or at a temperaturegreater than room temperature (e.g., 40° C., 50° C., 75° C., 100° C.,150° C., 200° C., 300° C., 500° C., etc.).

Sizing the electrode S280 functions to modify a size and/or shape of theelectrode and/or collector. S280 is typically performed after S260, butcan be performed before and/or simultaneously with S260. The electrodesare preferably sized to approximately the same dimensions (e.g., haveapproximately the same area). The separator is preferably larger thanthe electrodes (e.g., larger in each direction orthogonal to parallelnormals of broad faces of the electrodes such as by 1 mm, 2 mm, 3 mm, 5mm, etc.; 1%, 2%, 5%, 10%, 20%, etc. of the electrode size; etc.).However, different electrodes can have different sizes. Similarly, theelectrodes preferably fill the housing area (e.g., electrode area isabout 80-95% of an internal area of the housing), which is beneficialfor minimizing excess material and thereby increasing an energy densityof the battery (e.g., by having less weight that does not contribute tothe energy). However, the electrodes can fill any suitable portion ofthe housing interior.

The electrodes can be sized simultaneously and/or separately. Sizing theelectrodes can include cutting the electrodes (e.g., using a cutter, diecutter, etc.), dinking the electrodes, tearing the electrodes, machiningthe electrodes, and/or any suitable steps or processes.

Assembling the battery S300 can function to attach the batterycomponents together to form the battery. The battery can be assembled inline with (e.g., using a machine connected to) an electrodemanufacturing machine and/or can be separate from the electrodemanufacturing machine.

As shown for example in FIG. 5 , assembling the battery cell caninclude: contacting the electrodes S320 (e.g., across a separator),enclosing the electrodes in a housing S340 (e.g., inserting theelectrodes into, placing the electrodes into, surrounding the electrodeswith, etc. the housing), adding electrolyte to the electrodes S360(e.g., within the housing), sealing the housing S380, and/or anysuitable steps.

The electrodes can be contacted S320 using a roll-to-roll process (e.g.,as shown for example in FIG. 3 ), by stacking the electrodes (e.g.,before or after cutting to size using a die cutter or other cutter),and/or otherwise be contacted.

The housing can be sealed S380 using sealing tape, welding, crimping,vacuum sealing, and/or any suitable sealing mechanism. The housing canbe a pouch (e.g., to form a pouch cell), cylindrical (e.g., to form acylindrical cell), prismatic (e.g., to form a prismatic cell), and/orhave any suitable format. In some variants (e.g., for liquidelectrolyte, for a semifluid electrolyte, etc.), the housing can bepartially sealed (e.g., along 3 sides for a 4-sided housing) to form avolume that can hold the electrolyte. After electrolyte is added S340(e.g., poured in, aliquoted in, etc.), the housing can be fully sealed.However, the housing can be sealed in any manner.

The electrodes can be connected to tabs (e.g., such as an aluminium tab111 for the cathode and a nickel tab 121 for the anode which canfunction to allow the cell to connect to a load, other battery cells toform a pack, etc.) that extend outside of the battery housing (as shownfor example in FIG. 4A) and/or form a tabless battery (e.g., as shownfor example in FIG. 4B such as to enable electrical contact to be madethrough the battery housing). However, the electrodes can otherwise becontacted.

The tabs for the electrodes can be on the same, adjacent, opposite,and/or any suitable sides of the battery and/or electrode. For example,as shown in FIG. 6A or FIG. 6B, the anode and cathode can have tabs onthe same side of the battery. In another example, as shown in FIG. 6C,the anode and cathode can have tabs on opposite ends of the battery.However, the tabs can be arranged in any suitable portion of the batteryand/or electrode (e.g., a plurality of sides).

The tabs can extend along approximately the full length of an electrode(e.g., as shown for example in FIG. 6B or FIG. 6C, length, width,diagonal dimension, diameter, etc.), along a predetermined extent of theelectrode (e.g., as shown for example in FIG. 6A; such as 5%, 10%, 20%,25%, 30%, 50%, 75%, values or ranges therebetween of the length, width,diagonal, diameter,, etc.; such as 1 mm,2 mm, 5 mm, 10 mm, 15 mm, 20 mm,25 mm, 30 mm, 50 mm, 100 mm, values or ranged therebetween, etc.; etc.),and/or for any suitable extent of the battery. Having a tab that extendsalong approximately the full length of an electrode can be beneficialfor providing greater contact area (e.g., between the tab and theelectrode).

In some variants (e.g., for pouch batteries), there can be apredetermined space (typically between 10-15 mm, but it can be larger orsmaller) between the cell electrode and pouch end. In some embodiments,it can be beneficial to reduce (e.g., minimize) the predetermined spaceto save overall space of the battery, reduce a weight of the battery,and/or can otherwise be beneficial. The predetermined space can bereduced, for example, using sonic or ultrasonic welders we can minimizea metal weld down to 2 mm, using a plastic or polymer adhesive weld (orheat seal) can reduce an adhesive connection down to 2-3 mm (e.g., whenwe seal the cell after adding electrolyte). Typically, excess space (onthe order of about 500 um – 1 mm, but can be smaller than 500 µm orlarger than 1 mm) of extra space is retained for the separator so itcovers the edge of the electrodes. As a result, a battery can have apredetermined space down to 5 mm (or potentially smaller; as shown forexample in FIG. 6 ). The adhering (e.g., welding) steps can be performedwith one machine or a plurality of different machines. The adheringsteps can be performed manually (e.g., by hand) or automatically (e.g.,in a roll to roll process). In some variations, plastic welding on theedges of the battery can be used to reduce the excess foil on the sides(e.g., reducing the excess foil from 3-5 m down to 2 mm or less).Reducing the amount of excess foil and/or predetermined space canincrease the Wh/L or Wh/kg of the cell (e.g., by less than 0.01%, 0.01%,0.1%, 1%, 10%, values therebetween, etc.). Plastic welding canadditionally be beneficial as it can be performed at low temperatures(e.g., room temperature, less than about 0° C., 10° C., 20° C., 50° C.,100° C., etc.) avoiding potential problems resulting from heating thebattery (and/or constituents thereof).

Conditioning the battery S400 can function to modify (e.g., extend) alifetime of the battery. For example, conditioning the battery canincrease and/or decrease a charge state of the battery (e.g., state ofcharge) to protect the battery from battery aging conditions. Forinstance, when a temperature (or an expected temperature such as atemperature swing anticipated during shipping or transportation) isgreater than a threshold temperature, the battery can be discharged todecrease aging of the battery. However, the battery can be conditionedin response to any suitable situation (e.g., environment, battery state,etc.) and/or the battery can not be conditioned.

Assessing a quality of the battery S500 functions to measure one or morebattery property (particularly with a goal of ensuring batteries areconsistent between instances of the method such as instances usingdifferent batches of electrode materials). Battery properties caninclude: electrode thickness, electrode capacity, energy density,lifetime, state of charge, state of health, state of power, voltage(e.g., open circuit voltage, instantaneous voltage, etc.), current(e.g., short circuit current, instantaneous current), temperature,impedance, thermodynamic properties (e.g., entropy, enthalpy, etc.),and/or any suitable properties. For example, assessing a quality of thebattery(s) can include charging and/or discharging the battery at one ormore charging rates while measuring the battery property (and/ormeasuring a property correlated with the battery property). However, thequality of the battery can otherwise be assessed.

Embodiments of the system and/or method can include every combinationand permutation of the various system components and the various methodprocesses, wherein one or more instances of the method and/or processesdescribed herein can be performed asynchronously (e.g., sequentially),concurrently (e.g., in parallel), or in any other suitable order byand/or using one or more instances of the systems, elements, and/orentities described herein.

As a person skilled in the art will recognize from the previous detaileddescription and from the figures and claims, modifications and changescan be made to the preferred embodiments of the invention withoutdeparting from the scope of this invention defined in the followingclaims.

We claim:
 1. A method for forming a battery anode comprising: forming aslurry comprising: binder; conductive additive; and active materialcomprising silicon particles, wherein the silicon particles comprise aninternal surface area between about 50 and 200 m²/g and an externalsurface area between about 10 and 20 m²/g; depositing the slurry on acurrent collector; drying the deposited slurry to form a deposited film;and compacting the deposited film to form the battery anode.
 2. Themethod of claim 1, wherein the silicon particles comprise between about1 and 10% carbon by mass, between about 1 and 5% oxygen by mass, andbetween about 85 and about 98% silicon by mass.
 3. The method of claim1, wherein the silicon particles comprise a nonspheroidal morphology. 4.The method of claim 3, wherein the silicon particles comprise apolyhedral morphology.
 5. The method of claim 1, wherein the activematerial further comprises graphite.
 6. The method of claim 5, whereinthe graphite comprises graphitic particles with a diameter between about10 and 50 µm, wherein the silicon particles fill interstitial spacesbetween the graphitic particles within the battery anode.
 7. The methodof claim 6, wherein compacting the deposited film comprises calenderingthe deposited film, wherein a density of the deposited film increases bybetween about 30% and 50% during calendering.
 8. The method of claim 6,wherein the deposited film comprises between about 70% and 90% activematerial by mass, between about 5% and 20% conductive material by mass,and between about 5 and 10% binder by mass.
 9. The method of claim 5,wherein the active material comprises between about 30% and 50% siliconparticles by mass and between about 50% and 70% graphite.
 10. The methodof claim 1, wherein the conductive additive comprises C65 black carbon,and wherein the binder comprises an approximately one to one mixture ofcarboxymethyl cellulose and styrene-butadiene rubber.
 11. The method ofclaim 1, wherein the silicon particles comprise a carbonaceous coating,wherein a surface area of the carbonaceous coating is between about 5and 10 m²/g.
 12. The method of claim 1, wherein the silicon particlescomprise an external volume expansion of at most about 15% duringlithiation.
 13. The method of claim 1, wherein the silicon particles aremanufactured from silica fumes that are reduced to silicon.